Table 1 Examples of technologies for the removal or mitigation of arsenic [Sources: [26, 27]]
Technology (Intervention) | Mechanism of action |
|---|---|
Pre-oxidation of arsenic(III) to arsenic(V) | By transforming to one form of arsenic, simplifies arsenic removal by other means |
Precipitation and coagulation | Co-precipitation of water insoluble arsenates and inorganic oxides of other metals |
Adsorption | Granular adsorptive media |
Membrane | Filtration, electrical repulsion and adsorption |
Ion exchange | Water passes through an ion exchange resin which removes arsenic by exchanging it for non-toxic ions. |
Biological removal | Sorption and oxidation, e.g. through bacteria, fungi and hyacinths |
Dugwell | The top of shallow aquifers, at less than 10 m, appear to be less contaminated than deeper water. |
Deep tubewells | Tubewells sunk below the layer of sediment considered to contain arsenic |
Reverse osmosis | Contaminated water is forced through a membrane. The treated water passes through leaving the arsenic ions on the membrane |
Nanofiltration | Similar principle to reverse osmosis, with a nm pore size |